 
strict digraph loopgraph {
    rankdir=BT;
    node[color=blue, fillcolor=lightblue, style=filled];

    L1->L4->L8;
    L2->L4->L6->L8; L6->L9;
    L3->L5->L7->L9;
    L1->L7;

    {rank=same; L4 L7}


}